Sunday 19 January 2014 14.39 EST
First published on Sunday 19 January 2014 14.39 EST

David Moyes has unquestionably made mistakes as the Manchester United manager but in the aftermath of this defeat he must have reflected on his decisions and wondered what he could have done differently.

Throughout the first half United played good football, entering the final third readily and putting together some decent passing moves, particularly down the left. The difference was in the penalty areas, where Chelsea were more clinical in front of goal and more solid at the back.

United started extremely brightly, closing down high up the pitch and dominating possession within Chelsea's half. They found gaps between the lines, with José Mourinho roaring at David Luiz to sit deeper and help protect the defence. Chelsea lacked a reliable defensive midfielder and someone who could play calm passes under pressure, the precise roles in which the £21m signing Nemanja Matic specialises.

The most significant feature of United's play was the positioning of Adnan Januzaj, who played high up the pitch alongside Danny Welbeck. It was not uncommon to see Welbeck dropping off into deeper positions to pressure David Luiz or Ramires, while Januzaj drifted towards the left as United's most advanced attacker.

Danny Welbeck dropped into midfield, leaving Adnan Januzaj highest up the pitch, which caused problems towards the left for Branislav Ivanovic and Gary Cahill

Januzaj was crucial in United's numerical superiority on the left, a key feature of Moyes's coaching philosophy. United created various chances down that flank. Ashley Young had a shot saved by Petr Cech after a one-two with Welbeck and Patrice Evra fired into the side-netting. Much of United's play revolved around Januzaj: he intelligently squared for Welbeck, who got the ball under his feet amid pressure from César Azpilicueta, before the 18-year-old hit a ball across the six-yard box, with no United attacker arriving at the far post.

United's profligacy is partly the result of them lacking their first‑choice strike partnership but there are no excuses for the frailties at the back. They conceded three goals without Chelsea penetrating in open play. Although the first goal was unfortunate, United's set‑piece defending for Samuel Eto'o's subsequent strikes was astonishingly bad, a simple case of not moving as a unit and poor marking. For that experienced players must take responsibility for individual mistakes, even if the consistent sloppiness suggests wider problems with concentration.

That was the difference between the sides. While he is renowned as an astute tactician, there is usually little surprising or revolutionary about Mourinho's approach. He simply carries out standard tactics with devastating efficiency because his players are focused, committed and fully understand their responsibilities.

Moyes could pinpoint his selection decisions here, in particular the role of Januzaj, as the reason United caused problems in the first half. Peculiarly, United's main weakness is their lack of class in midfield. Here they dominated the centre but lacked quality at both ends.